Equilibrium potential

Equilibrium Potential

The Equilibrium Potential (pronounced: ee-kwuh-lib-ree-uhm poh-ten-shuhl) is a term used in neuroscience and physiology to describe the electrical potential difference across the cell membrane that would result in no net ion movement of a particular ion in or out of the cell.

Etymology

The term "Equilibrium Potential" is derived from the words "equilibrium", which means a state of balance, and "potential", which in this context refers to the potential difference or voltage across the cell membrane.

Definition

The Equilibrium Potential is the membrane potential at which the net flow of a specific ion across the cell membrane is zero. This is due to the balance between the chemical gradient and the electrical gradient for that ion. It is a key concept in understanding the resting membrane potential and the changes that occur during an action potential.

Calculation

The Equilibrium Potential for an ion can be calculated using the Nernst equation, which takes into account the temperature, the charge of the ion, and the concentration of the ion inside and outside the cell.

Related Terms

Resting Membrane Potential: The membrane potential of a cell at rest, which is determined by the equilibrium potentials of various ions.
Action Potential: A rapid, temporary change in the membrane potential, which is caused by the movement of ions across the cell membrane.
Nernst Equation: An equation used to calculate the equilibrium potential for an ion.
Ion Channel: A protein that allows specific ions to move across the cell membrane.
Ion Pump: A protein that actively transports ions across the cell membrane.